Drug-filled stents have been presented as an alternative or complement to conventional drug-coated stents with a coating of drug-polymer or pure drug. With drug-filled stents, the stent struts have a drug-filled center. An example of a stent strut having a drug-filled center is described in US Publication No. 2011/0008405, entitled “Hollow Tubular Drug Eluting Medical Devices,” which is incorporated herein by reference in its entirety for all purposes. After implantation, the drug is released out of holes formed in the stent struts. The drug contained within the stent struts is protected from potential damage when the stent is crimped onto a carrier, such as a balloon catheter, and during the process of positioning the stent and catheter through a patient's vasculature to a target treatment site.
A visualization method that relies on the radiopacity of the stent is often used to determine whether the stent is properly located at the target treatment site. The struts of drug-filled stents may be less radiopaque as they are hollow compared to conventional drug-coated stents having only solid metal wire struts. The reduction in radiopacity can make it difficult to visualize the stent. Accordingly, there is a need to improve radiopacity of drug-filled stents.